import { Injectable, Logger } from '@nestjs/common';
import { PrismaService } from '../../database/prisma.service';
import { VideoGenerationProducer } from '../video-queue/video-generation.producer';
import { EventsGateway } from '../events/events.gateway';

@Injectable()
export class DashboardService {
  private readonly logger = new Logger(DashboardService.name);

  constructor(
    private readonly db: PrismaService,
    private readonly videoGenerationProducer: VideoGenerationProducer,
    private readonly eventsGateway: EventsGateway,
  ) {}

  /**
   * Dashboard istatistiklerini hesaplar.
   * UserID bazlı filtreleme — her kullanıcı kendi verilerini görür.
   * Gerçek plan bilgisini Subscription → Plan tablosundan çeker.
   */
  async getStats(userId: string) {
    const [
      totalProjects,
      completedVideos,
      activeRenderJobs,
      failedProjects,
      draftProjects,
      totalCreditsUsed,
      recentProjects,
      activeSubscription,
      creditBalance,
    ] = await Promise.all([
      // Toplam proje sayısı
      this.db.project.count({
        where: { userId, deletedAt: null },
      }),

      // Tamamlanan video sayısı
      this.db.project.count({
        where: { userId, status: 'COMPLETED', deletedAt: null },
      }),

      // Aktif render job sayısı
      this.db.project.count({
        where: {
          userId,
          deletedAt: null,
          status: { in: ['PENDING', 'GENERATING_MEDIA', 'RENDERING', 'GENERATING_SCRIPT'] },
        },
      }),

      // Başarısız projeler
      this.db.project.count({
        where: { userId, status: 'FAILED', deletedAt: null },
      }),

      // Draft projeler
      this.db.project.count({
        where: { userId, status: 'DRAFT', deletedAt: null },
      }),

      // Toplam harcanan kredi
      this.db.project.aggregate({
        where: { userId, deletedAt: null },
        _sum: { creditsUsed: true },
      }),

      // Son 5 proje
      this.db.project.findMany({
        where: { userId, deletedAt: null },
        orderBy: { createdAt: 'desc' },
        take: 5,
        select: {
          id: true,
          title: true,
          status: true,
          progress: true,
          thumbnailUrl: true,
          finalVideoUrl: true,
          videoStyle: true,
          aspectRatio: true,
          language: true,
          sourceType: true,
          createdAt: true,
          updatedAt: true,
          completedAt: true,
        },
      }),

      // Kullanıcının aktif aboneliği (plan dahil)
      this.db.subscription.findFirst({
        where: {
          userId,
          status: { in: ['active', 'trialing'] },
        },
        include: { plan: true },
        orderBy: { createdAt: 'desc' },
      }),

      // Bu ayki net kredi bakiyesi (CreditTransaction tablosundan)
      this.db.creditTransaction.aggregate({
        where: {
          userId,
          createdAt: {
            gte: new Date(new Date().getFullYear(), new Date().getMonth(), 1),
          },
        },
        _sum: { amount: true },
      }),
    ]);

    // Plan bilgisini aktif abonelikten çek, yoksa free plan varsayılanları
    const plan = activeSubscription?.plan;
    const currentPlan = plan?.name || 'free';
    const monthlyLimit = plan?.monthlyCredits ?? 3;
    const maxDuration = plan?.maxDuration ?? 30;
    const maxResolution = plan?.maxResolution ?? '720p';

    // Kredi hesaplama: CreditTransaction tablosundan kalan bakiye
    const creditsUsed = totalCreditsUsed._sum.creditsUsed || 0;
    const netCreditBalance = creditBalance._sum.amount || 0;
    const creditsRemaining = Math.max(0, netCreditBalance);

    return {
      totalProjects,
      completedVideos,
      activeRenderJobs,
      failedProjects,
      draftProjects,
      totalCreditsUsed: creditsUsed,
      creditsRemaining,
      monthlyLimit,
      currentPlan,
      maxDuration,
      maxResolution,
      recentProjects,
    };
  }

  /**
   * Kuyruk durumunu BullMQ ve Worker kuyruğundan alır.
   */
  async getQueueStatus() {
    const queueStats = await this.videoGenerationProducer.getQueueStats();
    const wsClients = this.eventsGateway.getConnectedClientsCount();

    return {
      queue: queueStats,
      websocket: {
        connectedClients: wsClients,
      },
    };
  }

  /**
   * Bu ay üretilen videoların gün bazlı dağılımı (chart verisi).
   */
  async getMonthlyChart(userId: string) {
    const startOfMonth = new Date();
    startOfMonth.setDate(1);
    startOfMonth.setHours(0, 0, 0, 0);

    const projects = await this.db.project.findMany({
      where: {
        userId,
        deletedAt: null,
        createdAt: { gte: startOfMonth },
      },
      select: {
        createdAt: true,
        status: true,
      },
      orderBy: { createdAt: 'asc' },
    });

    // Gün bazlı gruplama
    const dailyMap: Record<string, { created: number; completed: number }> = {};
    projects.forEach((p) => {
      const day = p.createdAt.toISOString().split('T')[0];
      if (!dailyMap[day]) dailyMap[day] = { created: 0, completed: 0 };
      dailyMap[day].created++;
      if (p.status === 'COMPLETED') dailyMap[day].completed++;
    });

    return Object.entries(dailyMap).map(([date, counts]) => ({
      date,
      ...counts,
    }));
  }
}